package org.bouncycastle.asn1.x509;

import org.bouncycastle.asn1.ASN1Choice;
import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERBMPString;
import org.bouncycastle.asn1.DERIA5String;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERString;
import org.bouncycastle.asn1.DERUTF8String;
import org.bouncycastle.asn1.DERVisibleString;

/**
 * <code>DisplayText</code> class, used in <code>CertificatePolicies</code> X509 V3 extensions (in policy qualifiers).
 * 
 * <p>
 * It stores a string in a chosen encoding.
 * 
 * <pre>
 * DisplayText ::= CHOICE {
 *      ia5String        IA5String      (SIZE (1..200)),
 *      visibleString    VisibleString  (SIZE (1..200)),
 *      bmpString        BMPString      (SIZE (1..200)),
 *      utf8String       UTF8String     (SIZE (1..200)) }
 * </pre>
 * 
 * @see PolicyQualifierInfo
 * @see PolicyInformation
 */
public class DisplayText extends ASN1Encodable implements ASN1Choice {
    /**
     * Constant corresponding to ia5String encoding.
     * 
     */
    public static final int CONTENT_TYPE_IA5STRING = 0;
    /**
     * Constant corresponding to bmpString encoding.
     * 
     */
    public static final int CONTENT_TYPE_BMPSTRING = 1;
    /**
     * Constant corresponding to utf8String encoding.
     * 
     */
    public static final int CONTENT_TYPE_UTF8STRING = 2;
    /**
     * Constant corresponding to visibleString encoding.
     * 
     */
    public static final int CONTENT_TYPE_VISIBLESTRING = 3;

    /**
     * Describe constant <code>DISPLAY_TEXT_MAXIMUM_SIZE</code> here.
     * 
     */
    public static final int DISPLAY_TEXT_MAXIMUM_SIZE = 200;

    int contentType;
    DERString contents;

    /**
     * Creates a new <code>DisplayText</code> instance.
     * 
     * @param type
     *            the desired encoding type for the text.
     * @param text
     *            the text to store. Strings longer than 200 characters are truncated.
     */
    public DisplayText(int type, String text) {
        if (text.length() > DISPLAY_TEXT_MAXIMUM_SIZE) {
            // RFC3280 limits these strings to 200 chars
            // truncate the string
            text = text.substring(0, DISPLAY_TEXT_MAXIMUM_SIZE);
        }

        contentType = type;
        switch (type) {
            case CONTENT_TYPE_IA5STRING:
                contents = (DERString) new DERIA5String(text);
                break;
            case CONTENT_TYPE_UTF8STRING:
                contents = (DERString) new DERUTF8String(text);
                break;
            case CONTENT_TYPE_VISIBLESTRING:
                contents = (DERString) new DERVisibleString(text);
                break;
            case CONTENT_TYPE_BMPSTRING:
                contents = (DERString) new DERBMPString(text);
                break;
            default:
                contents = (DERString) new DERUTF8String(text);
                break;
        }
    }

    /**
     * Creates a new <code>DisplayText</code> instance.
     * 
     * @param text
     *            the text to encapsulate. Strings longer than 200 characters are truncated.
     */
    public DisplayText(String text) {
        // by default use UTF8String
        if (text.length() > DISPLAY_TEXT_MAXIMUM_SIZE) {
            text = text.substring(0, DISPLAY_TEXT_MAXIMUM_SIZE);
        }

        contentType = CONTENT_TYPE_UTF8STRING;
        contents = new DERUTF8String(text);
    }

    /**
     * Creates a new <code>DisplayText</code> instance.
     * <p>
     * Useful when reading back a <code>DisplayText</code> class from it's ASN1Encodable/DEREncodable form.
     * 
     * @param de
     *            a <code>DEREncodable</code> instance.
     */
    public DisplayText(DERString de) {
        contents = de;
    }

    public static DisplayText getInstance(Object de) {
        if (de instanceof DERString) {
            return new DisplayText((DERString) de);
        } else if (de instanceof DisplayText) {
            return (DisplayText) de;
        }

        throw new IllegalArgumentException("illegal object in getInstance");
    }

    public static DisplayText getInstance(ASN1TaggedObject obj, boolean explicit) {
        return getInstance(obj.getObject()); // must be explicitly tagged
    }

    public DERObject toASN1Object() {
        return (DERObject) contents;
    }

    /**
     * Returns the stored <code>String</code> object.
     * 
     * @return the stored text as a <code>String</code>.
     */
    public String getString() {
        return contents.getString();
    }
}
